The const keyword was introduced in ES6 (2015)
Variables defined with const cannot be Redeclared
Variables defined with const cannot be Reassigned
Variables defined with const have Block Scope
Cannot be Reassigned
A variable defined with the const keyword cannot be reassigned:
Example
const PI = 3.141592653589793;
PI = 3.14; // This will give an error
PI = PI + 10; // This will also give an error